Java based Viewers

Free

Panorado Applet is a Java viewer applet. It only shows a "flat" view but it is fast, so it is suited for larger images where the normal immersive-style warping isn't needed.

PURE Player for Java (by ImmerVision) is a Java viewer applet that supports cylindrical, spherical and cubic panoramic images.

PURE Player for PRO Java (by ImmerVision) is a free Java viewer applet that supports cylindrical, spherical and cubic panoramic images. It also supports user interfaces.

Commercial

There are some commercial Java based viewers. Most of them are either a PTViewer clone or less functional.

HTML5 based Viewers

Free

Syborg Rooms exports virtual tours in flash and html5. Based on the users device the export shows the supported format.

VR5 Pano Viewer. You need to prepare the images to him (cube faces in 2 resolutions: 1024px & 480px. Can redirect to your standard player in case the browser is not on an iPad/iPhone. (Free for personal use.)

Pannellum Very lightweight HTML 5 open source viewer featuring embedding support, configuration using URL parameters, title and author information, multiresolution support, and full screen support among other things.

Leanorama. A free and open source viewer for Webkit browsers (Chrome, Safari, iPad, iPhone, Android 3+). Allows simple definition of virtual tours in JavaScript. Will stretch cube faces of any size to 1024*1024px - so larger panoramas probably won't make sense. Documentation and download on GitHub

Commercial

KRPano is a Flash 9 & 10 & HTML5 based panorama viewer with a wide range of configuration options. These include different projections such as stereographic ('little planet'), fisheye, Vedutismo, and 'architectural'. It can handle cubefaces, equirects and QTVR .mov files, and it can embed other media including audio and FLV videos into panoramas.

An open source panoramic image viewer and perspective tool for all Qt platforms, including Linux, Windows, OSX. It can display files in many panoramic formats. Your video driver must support OpenGL version 1.5, 2.0 for full functionality. Get Panini at [1], build on macOS or build on other unixes.

For iPad, iPhone and iPod Touch is an app that plays panoramas (max. 2048x1024px equirects on iPhone/iPod, 4096x2048 on iPad) using OpenGL. The standard version of PangeaVR is free, the Pro version (which can store panoramas locally for offline viewing) costs $5.99.

A commercial full-featured Android (from 2.0) App by Andridea (author is Andrea de Carolis) to view Panorama up to 2.27GigaPixel (max 65000x32000) on tablets/smartphones with Kinetic Rotation, full pinch and zoom, tagging. Take a jpeg (equirectangular/cylindrical, full or semi panoramic) and processes it with its own multi-tiles generator, and view them offline with its hardware accelerated 3d viewer. User can change FOV, vert/horiz degree and many options (developer site). There'is also a free demo available, with some limitations. Developers offer the possibility to build Virtual Tour App.

Commercial

x

Flash(deprecated) or Shockwave(discontinued) based Viewers

Free

CuTy is a tiny, dedicated viewer for (single node, JPEG encoded, cubic) QTVR .mov files based for Flash Player 10 and newer. Its functionality is deliberately kept minimal.

PanoSalado is an open source Flash 10 and Flex based viewer for cubic, equirectangular (spherical), cylindrical and QTVR panoramas. It handles multi-resolution tiled panoramas, and playback of panoramic video in common projections. It supports 2D & 3D hotspots, audio, video, and being extended via XML or directly via Actionscript (AS3) and/or MXML. See PanoSalado's blog, download source and examples from the IVRPA repository and access the API.

Salado Player is a fork from PanoSalado created in 2010. SaladoPlayer features configuration via xml files and additional modules, along with a module api.

PURE Player for Flash is a free Flash 9 based player that supports cylindrical, spherical and cubic panoramas.

SPi-V is a very sophisticated and smooth viewer based on Macromedia Shockwave that handles panoramas completely in graphics card memory (free version with logo).

Syborg Rooms can connect multiple panoramas and enrich the expierence with videos, images and text. Rooms are build with Syborg Architect - an easy graphical interface. It supports iPhone and iPad as well.

Commercial

The Flash Panorama Player is a cross-platform viewer that displays QTVR movies as well as equirectangular (spherical) and cylindrical panoramas. Cube faces and stripes can also be handled. It supports SWF-plugins to extend its functionality (for example to integrate distorted FLV-movies as hotspots).

Pano2VR (formerly Pano2QTVR) creates HTML5 virtual tours, and Flash 10-compatible SWF files with included spherical viewer. It also creates QuickTime VR content and can output images in a number of different projections including equirect and cubefaces.

KRPano is a Flash 9 & 10 & HTML5 based panorama viewer with a wide range of configuration options. These include different projections such as stereographic ('little planet'), fisheye, Vedutismo, and 'architectural'. It can handle cubefaces, equirects and QTVR .mov files, and it can embed other media including audio and FLV videos into panoramas.

Plugin based Viewers (For all modern browsers support has ended for all NPAPI plugins.)

Free

Quicktime is available for Apple Macintosh. Requires panorama in QTVR movie format. (PanoCube or Pano2QTVR convert from equirectangular to .mov on Windows)

freepv is an open source cross-platform viewer for QTVR and other panorama formats.